The Building Conservation Directory 2020

156 T H E B U I L D I N G C O N S E R VAT I O N D I R E C T O R Y 2 0 2 0 C AT H E D R A L C O MM U N I C AT I O N S with judgement on the prominent parts… so as to produce the best effect.’’ Another curious technique from the mid- 18th century is the use of metal powders mixed into a paint to create the effect of Verdigris patinated copper on doors. It is the replication of patination that often gives faux finishes their lifelike quality. Generally, because most metallic powders are stable and non-reactive in the short term, they can be bound in oil, making them suitable for painting a vast array of substrates, including timber, plaster, metal, stone, glass and others. However, due to the tendency of most metals to oxidise over a period of time, most metal powders will dull and lose their lustre after a number of years. This is an inevitability and something which is accepted. Because oxidisation accelerates outside, any gold paint found externally will most likely be made with genuine gold powder. In contrast, there is one mineral pigment which has been revered for its gold-like qualities, orpiment. This was the only bright yellow pigment available pre 15th century (other than the far duller yellow ochre) and is a naturally occurring mineral form of arsenic sulphide. (‘Arsenic’ incidentally comes from the word Zarnikh or Zar, the Persian word for gold.) Its use is almost as far reaching as gold itself; a bag of the powdered pigment was found on the floor of Tutankhamun’s tomb, it adorns the walls of the Taj Mahal and even pops up in the 9th century Book of Kells. Today, imitation gold paint and other faux finishes are most likely to be found in theatres, cinemas, opera houses and other ‘theatrical’ public buildings such as public houses and even libraries. Often these used cheap lustre powders such as mica to make faux gold paint, mainly as a cost saving exercise as the expense needed to decorate these palatial interiors would have been immense. Faux gold and a variety of other shiny metals and faux finishes were often used in abundance to help create the aesthetic required, be it drama, storytelling or theatrical exuberance and excess. But the glitter and sparkle also served a more practical purpose of bouncing light around the otherwise dark, often windowless interior. In the words of Shakespeare – ‘All that glisters is not gold.’ Recommended Reading Ian C Bristow, Interior House Painting Colours and Technology 1615–1840, Paul Mellon Center for Studies in British Art 1996 The Art of Gold Beating (1959) British Pathe: https://www.youtube.com/ watch?v=2Lak64SAaIY iWonder: Life in colour: the surprising story of paint . Dr Erma Hermens: www.bbc.com/ timelines/zqytpv4 Museums and Galleries Commission, Science for Conservators. Volume 1: An introduction to Materials , Taylor & Francis Ltd, 1992: and Science for Conservators. Volume 2: Cleaning, Routledge 2005 ALEXANDRA MILLER BSc is Decorative Arts Section Manager and Senior Project Manager at Cliveden Conservation (see page 161). A bronze paint-effect created by Cliveden Conservation for a new statue of Minerva at Pitzhanger Manor and, below, a detail of the finish: this effect was created using modern mica powder in an orangey yellow varnish. (Photos: Alexandra Miller by kind permission of Pitzhanger Manor & Gallery Trust) their craft, that the imitations became as sought after as the real thing – and as demand increased, sometimes just as expensive. As Ian Bristow explained in Interior House Painting Colours and Technology 1615–1840 (p133); “A considerable part of the house- painter’s skill,… lay in the imitation of various fine materials, especially different varieties of marble and finer cabinet timbers… (as well as) bronze, tortoise-shell and mother-of-pearl”. Although this article focuses on gold, it is important to put it into the context of the overall interior. The faux finishes (as well as the genuine) were sitting together in grand schemes. Where you would find genuine gold leaf you would also find genuine marble and fine timber, and the same is to be said for faux finishes. There are even examples of faux mother-of-pearl, faux cast bronze and imitation gold brocade fabric being painted directly over genuine gold and silver leaf. It was entirely dependent on the whim and purse strings of the patron. Metal powders were used to recreate many of these effects because of the unrivalled lustre they offered, that is almost impossible to recreate with pigment alone. The metals used for the faux finishes were chosen because they were far cheaper and more abundant than the real thing. For example, the ‘gold’ powder described in 1764 by Robert Dossie in The Handmaid to the Arts ¹ was made from ground up Dutch metal leaf (a thin leaf of copper/ zinc alloy) which came in a variety of golden shades. He also listed several different metals, minerals and other ‘metallic powders’ that could be used on ‘plaister or other busts and figures in order to make them appear as if cast of copper or metals.’ The trouble with almost all of these metal powders is their tenancy to tarnish and dull over time, giving them a muddy brassy appearance. Most modern fine decorators and artists now widely use inert mica powder to give lustre to paint, which does not tarnish. This mineral is so inert and stable that it is widely used in makeup. However, mica has a different kind of lustre to more traditional metal powders as it is finer and the result looks a bit more synthetic. When used as infill for small repairs in original metallic faux finishes, mica tends to stand out, and in this instance it is best to use traditional bronze powder, hand mixed to match the colour of the surrounding finish. However, in applications where there is no older finish to match, mica is preferable and gives very satisfactory results. An excellent example of modern mica powder being used to make metallic paint in place of metal powder is on the faux-bronzed statue of Minerva at Pitzhanger Manor, Ealing. A common method used historically for creating faux cast bronze was described by Knight and Lacey in The Painters’ and Varnishers’ Pocket Manual in 1825: ‘’For the ground, after it has been rubbed down, take Prussian Blue, verditer and spruce ochre. Grind them separately in water, turpentine or oil according to the nature of the work and mix them in such proportions as are required to produce the colours desired, then grind Dutch Metal in a part of this composition, laying it ¹ Cited by Ian C Bristow in Interior House Painting Colours and Technology 1615–1840 , p140